cosmopolitan/libc/dns/gethoststxt.c
Justine Tunney 68c7c9c1e0
Clean up some code
- Use good ELF technique in cosmo_dlopen()
- Make strerror() conform more to other libc impls
- Introduce __clear_cache() and use it in cosmo_dlopen()
- Remove libc/fmt/fmt.h header (trying to kill off LIBC_FMT)
2023-11-16 17:31:07 -08:00

96 lines
3.8 KiB
C

/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi│
╞══════════════════════════════════════════════════════════════════════════════╡
│ Copyright 2020 Justine Alexandra Roberts Tunney │
│ │
│ Permission to use, copy, modify, and/or distribute this software for │
│ any purpose with or without fee is hereby granted, provided that the │
│ above copyright notice and this permission notice appear in all copies. │
│ │
│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL │
│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED │
│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE │
│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL │
│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR │
│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER │
│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR │
│ PERFORMANCE OF THIS SOFTWARE. │
╚─────────────────────────────────────────────────────────────────────────────*/
#include "libc/calls/calls.h"
#include "libc/cxxabi.h"
#include "libc/dce.h"
#include "libc/dns/hoststxt.h"
#include "libc/dns/servicestxt.h"
#include "libc/intrin/bits.h"
#include "libc/intrin/pushpop.internal.h"
#include "libc/intrin/safemacros.internal.h"
#include "libc/macros.internal.h"
#include "libc/mem/mem.h"
#include "libc/runtime/runtime.h"
#include "libc/stdio/stdio.h"
#include "libc/str/str.h"
#include "libc/thread/thread.h"
static struct HostsTxt *g_hoststxt;
static struct HostsTxtInitialStaticMemory {
struct HostsTxt ht;
pthread_mutex_t lock;
struct HostsTxtEntry entries[8];
char strings[64];
} g_hoststxt_init;
static const char *GetHostsTxtPath(char *path, size_t size) {
if (!IsWindows()) {
return "/etc/hosts";
} else {
return GetSystemDirectoryPath(path, size, "drivers\\etc\\hosts");
}
}
/**
* Returns hosts.txt map.
*
* @note yoinking realloc() ensures there's no size limits
*/
const struct HostsTxt *GetHostsTxt(void) {
FILE *f;
char pathbuf[256];
struct HostsTxtInitialStaticMemory *init;
init = &g_hoststxt_init;
pthread_mutex_lock(&init->lock);
if (!g_hoststxt) {
g_hoststxt = &init->ht;
init->ht.entries.n = pushpop(ARRAYLEN(init->entries));
init->ht.entries.p = init->entries;
init->ht.strings.n = pushpop(ARRAYLEN(init->strings));
init->ht.strings.p = init->strings;
__cxa_atexit((void *)FreeHostsTxt, &g_hoststxt, NULL);
if ((f = fopen(GetHostsTxtPath(pathbuf, sizeof(pathbuf)), "r"))) {
if (ParseHostsTxt(g_hoststxt, f) == -1) {
/* TODO(jart): Elevate robustness. */
}
fclose(f);
}
}
pthread_mutex_unlock(&init->lock);
return g_hoststxt;
}
/**
* Frees HOSTS.TXT data structure populated by ParseHostsTxt().
*/
void FreeHostsTxt(struct HostsTxt **ht) {
if (*ht) {
if ((*ht)->entries.p != g_hoststxt_init.entries) {
free((*ht)->entries.p);
}
if ((*ht)->strings.p != g_hoststxt_init.strings) {
free((*ht)->strings.p);
}
if (*ht != &g_hoststxt_init.ht) {
free(*ht);
}
*ht = 0;
}
}